In , The Thran were a utopian race of humans whose technology level was much more advanced than any other Dominarians. Their artifact devices ran off of powerstones which had stable artificial planes in them. They were introduced in the Urza's Saga set, with such cards as http://ww2.wizards.com/gatherer/CardDetails.aspx?name=thran%20quarry Thran Quarry and http://ww2.wizards.com/gatherer/CardDetails.aspx?name=Thran%20Dynamo Thran Dynamo amongst others.